Molecular Differentiation of Gender in Buffalograss

Buffalograss [Buchloe dactyloides (Nutt.) Engelm. syn. Bouteloua dactyloides (Nutt.) Columbus] is a warm-season, stoloniferous, perennial grass species native to the Great Plains of North America. Buffalograss is a dioecious species where structural differences can be observed between inflorescences of male and female plants. The genetic mechanisms conferring gender expression in buffalograss are not known. In the present study, RNA-seq was performed to evaluate the transcriptome of 10 buffalograss female and 10 buffalograss male F1 individuals of a segregating diploid linkage mapping population. Collectively, 187,600,044 male sequencing reads and 148,324,220 female sequencing reads were produced. The sequencing reads were read mapped to a buffalograss cultivar Prestige reference transcriptome with a greater than 96% success rate. By comparing male and female transcriptomes, we found 1734 differentially expressed transcripts. Among this group, 445 transcripts had higher expression in male plants while the remaining 1289 had higher expression in the females. Two male-specific sequences and one female-specific sequence were identified along with genes associated with flowering and reproduction. To date, this is the most detailed characterization of the genetic differences between male and female buffalograss.